DESCRIPTION: (Applicant s abstract) People > 65 years of age are expected to exceed 50 million or 20% of the total population by the end of the century. The elderly undergo approximately 40% of all surgical procedures, amounting to an annual expenditure of over $60 billion. Our previous work demonstrated the postoperative in-hospital morbidity rate in octogenarians undergoing non- cardiac surgery to be 25%. By multivariate logistic regression, a history of neurological disease, congestive heart failure and arrhythmia increased the odds of developing any adverse postoperative events. Our work here focuses on the identification of the predictors of perioperative complications in geriatric surgical patients followed by clinical trials to modify the risk factor(s) in order to improve perioperative outcome. Four integrated clinical studies are planned: 1) A prospective, longitudinal cohort study of 600 consecutive geriatric surgical patients undergoing non-cardiac surgery. This study aims to determine the impact of perioperative complications on the functional status and long-term survival of the elderly surgical patients by measuring pre-defined in-hospital adverse postoperative outcomes, and functional and survival status at two years postoperatively. 2) A prospective cohort study of 200 geriatric patients undergoing non-cardiac surgery. This study aims to determine the accuracy of preoperative clinical methods of assessing heart function as compared to echocardiography; and also the prognostic relationship between preoperative diastolic dysfunction and postoperative heart failure. 3) A prospective cohort study of 300 patients undergoing coronary artery bypass graft surgery. This study aims to determine if left atrial dysfunction as measured by intraoperative transesophageal echocardiography provides incremental value in predicting the occurrence of postoperative atrial fibrillation when compared with routine clinical data. In later years, we will perform 4) a randomized, clinical trial of regional versus general anesthesia in 500 elderly patients undergoing orthopedic surgery. This study aims to determine the incidence of postoperative cognitive dysfunction and delirium between regional versus general anesthesia after controlling for intraoperative anesthetic and hemodynamic management and postoperative pain management. Postoperative cognitive function and delirium will be measured by standard neuropsychological tests and the Confusion Assessment Method. We believe that our studies will provide important results contributing ultimately to the improvement of perioperative outcomes in geriatric patients.